Improvement in expanding mandrels



.IQD. SMITH.

Expanding Mandrils. N0.138,947. PatentedMay131873.

AM, PHOTU-UTHOGRAPIIIC m H). (OSLMRHES P1200533) IINI'IED STATES PATENT OFFICE.

JAMES D. SMITH, OF NEW YORK, N. Y., ASSIGNOR TO JAMES D. SMITH AND k HUGH It. GARVIN, OF SAME PLACE.

IMPROVEMENT IN EXPANDING MANDRELS.

Specification forming part of Letters Patent No. 138,947, dated May 13, 1873; application filed August 1, 1872.

To all whom it may concern:

Be it known that I, JAMES D. SMITH, of the city, county, and State of New York, have invented an Improvement in Expanding Tools, of which the following is a specification:

This invention is applicable to mandrels, burrs, taps, and numerous other tools and work-shop appliances, in which a variable or adjustable diameter is desirable in order to fit them for various sizes or diameters of work. It consists in the combination, with atapering mandrel-piece, of a collar externally cylindrical, but corresponding internally to the taper of the mandrel piece, and slotted alternately from either end in such wise that,

by thrusting the mandrel-piece through the said collar to a greater or less degree, the collar may be expanded in a corresponding ratio, and thus brought to any diameter desired.

Figure l is a transverse section of an expanding tool made according to my invention. Fig. 2 is a longitudinal section of the same. Fig. 3 is a side view of the same.

A is the mandrel-piece, of tapering form and with its ends fitted for attachment to a lathehead, drill-slack, or other device or apparatus whereby the tool is to be put in operation for whatever special purpose the same may be designed. B is a collar, cylindrical externally, but with its bore or interior ofataperin gform, corresponding to the external contour of the mandrel-piece, the collar having, however only a portion of the length of the mandrel-piece, in order that it may be capable of a sliding movement thereon. Extending alternately inward from either end of the collar are longitudinal slots a, those starting from one end terminating in holes or enlargements a near the opposite end. As the collar is moved from a smaller to a larger part of the mandrel-piece, the tapering form of the latter spreads or expands the collar, this being, of course, readily permitted by the slots at. The slots extending equally from each end allow both to expand equally, and thereby, practically, the cylindrical external form of the collar is preserved whatever the extent of expansion.

In moving the collar from a larger to a smaller part of the mandrel-piece, its own elasticity causes it to contract upon the latter, the slots being narrowed in this case as they were broadened in the other. By this means the diameter of the device may be adjusted to any requisite degree or purpose by the simple longitudinal adjustment of the collar upon the mandrel.

Among many other functions which the invention may be made to-subserve is its use in the construction of expanding mandrels for use in lathes, of expanding boringinstruments, and the like. i

What I claim as my invention is The expanding tool, constituted by the tapering mandrel-piece and the cylindrical collar, formed with a tapering interior and slotted alternately from either end, the two combined and operating substantially as herein set forth.

Witnesses:

FRED. HAYNES, FERD. TUsoH.

JAS. D. SMITH. 

